Morphometric changes in pericyte-capillary endothelial cell associations correlated with vasoactive stimulus

The arterially-derived capillaries of the eel rete mirabile are heavily invested with highly arborized pericytes. By perfusing vasoactive agents through these capillaries, measuring changes in outflow volume and analyzing alterations in capillary and pericyte morphology a set of vasoactive agent-correlated changes were quantified. Morphometric analysis of the capillary ultrastructure revealed that alterations in flow and appearance were associated with changes in the extension of pericyte processes. These responses of the arterial pericytes to the vasoactive agents used in this study suggest that pericyte contraction alters the architecture of the arterially-derived capillaries of the rete in a manner which affects their permeability.